JP3668167B2 - Valve timing control device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a valve timing control device for an internal combustion engine that controls valve timing by changing the cam phase of an intake cam and / or an exhaust cam with respect to a crankshaft, and in particular, fixing a cam phase variable device that changes the cam phase. The present invention relates to a valve timing control device in which cleaning for preventing is performed.
[0002]
[Prior art]
This type of valve timing control device controls the charging efficiency and internal EGR by continuously changing the opening / closing timing of the intake valve and / or the exhaust valve and the valve overlap by changing the cam phase. This is intended to improve output and exhaust characteristics, and is disclosed in, for example, Japanese Patent Application Laid-Open No. 2000-104571. In this control device, the cam phase is changed by changing the relative angle of the intake cam with respect to the crankshaft by a cam phase variable mechanism in which the supply of hydraulic pressure is controlled by a hydraulic control valve. Also, in this control device, the hydraulic control valve and the cam phase variable mechanism are forcibly reciprocated between the most advanced position and the most retarded position in order to prevent sticking of the hydraulic control valve or the like due to foreign object biting. Cleaning is performed. This cleaning is performed only at the time of the deceleration fuel cut operation in which the operation of the internal combustion engine is not hindered and the throttle valve is in the fully closed state. Specifically, the cleaning is performed immediately when shifting to the deceleration fuel cut operation. It has become.
[0003]
[Problems to be solved by the invention]
However, in this control device, since cleaning is executed simultaneously with the start of the deceleration fuel cut, immediately after the intake pipe pressure fluctuates to the negative side due to the return of the throttle valve to the fully closed state, the intake air is released by executing the cleaning. When the valve is driven to the most advanced position and a large valve overlap with the exhaust valve occurs, positive pressure is introduced into the intake pipe through the exhaust valve and intake valve that are open at the same time, and the intake pipe internal pressure is increased to the positive pressure side. fluctuate. Thus, at the start of cleaning, immediately after the intake pipe pressure fluctuates to the negative pressure side, it suddenly fluctuates to the positive pressure side. Drivability will be impaired.
[0004]
The present invention has been made to solve such a problem, and is capable of reducing the backlash of the deceleration shock that accompanies the execution of cleaning, and the valve timing control device for an internal combustion engine that can increase the frequency of execution of the cleaning. The purpose is to provide.
[0005]
[Means for Solving the Problems]
In order to achieve this object, the present invention changes the cam phase CAIN, which is the phase of at least one of the intake cam 6a and the exhaust cam 7a, with respect to the crankshaft 8, thereby opening and closing at least one of the intake valve 4 and the exhaust valve 5. A valve timing control device for an internal combustion engine for controlling timing, wherein a camshaft (intake camshaft 6 in the embodiment (hereinafter the same in this section)) provided with at least one of an intake cam 6a and an exhaust cam 7a is used as a crankshaft. The cam phase varying device 11 that changes the cam phase CAIN by rotating it relative to 8 and the deceleration that determines whether or not the internal combustion engine 3 is in the deceleration fuel cut operation in which the supply of fuel is stopped during deceleration Fuel cut determination means (ECU 2, step 14 in FIG. 3) After Erukatto operation is started, when a predetermined delay time #TMVCLDY has elapsed, in order to prevent sticking of the cam phase varying apparatus 11 , Cam phase variable device 11 In the direction in which the overlap between the intake valve 4 and the exhaust valve 5 increases Force drive By And cleaning control means (ECU 2, steps 23, 16, and 17 in FIG. 3) for performing cleaning.
[0006]
According to this valve timing control device for an internal combustion engine, the cam phase of the intake cam and / or the exhaust cam is changed by rotating the cam shaft relative to the crankshaft by the cam phase varying device, and the intake valve and The opening / closing timing of the exhaust valve is controlled. Further, when a predetermined delay time has elapsed after the deceleration fuel cut operation of the internal combustion engine is started, the cam phase varying device is To increase the overlap between the intake and exhaust valves Force drive By Cleaning is executed. In this way, wait for the delay time to elapse after the deceleration fuel cut starts. , Since cleaning is executed, the intake pipe pressure that fluctuated to the negative pressure side due to the throttle valve being returned to the fully closed state immediately before the start of the deceleration fuel cut slightly returns to the positive pressure side and is stable before the cleaning is executed. It is in the state. Therefore, after that, when the cleaning is performed, a large valve overlap occurs between the intake valve and the exhaust valve, and even if a positive pressure is introduced into the intake pipe, the amount of fluctuation in the intake pipe internal pressure is small. As described above, fluctuations in the intake pipe internal pressure to the negative pressure side due to the fully closing of the throttle valve and fluctuations to the positive pressure side due to the execution of cleaning can be generated by shifting the timing. Driven back can be improved by making it possible to reduce the subsequent swaying and make it less likely to be felt as a shock.
[0007]
The invention according to claim 2 A valve timing control device for an internal combustion engine that controls the opening / closing timing of at least one of the intake valve 4 and the exhaust valve 5 by changing the cam phase CAIN that is at least one of the intake cam 6a and the exhaust cam 7a with respect to the crankshaft 8. The cam phase varying device 11 changes the cam phase CAIN by rotating a camshaft (intake camshaft 6) provided with at least one of the intake cam 6a and the exhaust cam 7a relative to the crankshaft 8. Then, the deceleration fuel cut determination means (ECU 2, step 14 in FIG. 3) for determining whether or not the internal combustion engine 3 is in the deceleration fuel cut operation in which the fuel supply is stopped during deceleration, and the deceleration fuel cut operation is started. After a predetermined delay time #TMVCLDY In addition, in order to prevent the cam phase varying device 11 from sticking, the cam phase varying device 11 is forcibly driven within a predetermined cam phase CAIN to thereby perform cleaning control (ECU2, FIG. 3). Steps 23, 16, 17), The gear ratio detecting means (gear position sensor 39) for detecting the gear ratio (gear position) of the transmission 21 connected to the internal combustion engine 3, and the delay time #TMVCLDY is set to a smaller value as the detected gear ratio is lower. Delay time setting means (ECU2, FIG. 4) for setting.
[0008]
According to this valve timing control device for an internal combustion engine, the cam phase of the intake cam and / or the exhaust cam is changed by the cam phase variable device, as in the first aspect of the present invention. The opening / closing timing is controlled. Further, after a delay fuel cut operation of the internal combustion engine is started, cleaning is executed by forcibly driving the cam phase varying device within a predetermined cam phase range when a predetermined delay time has elapsed. . Therefore, as in the case of the first aspect, the fluctuation of the intake pipe internal pressure to the negative pressure side due to the fully closing of the throttle valve and the fluctuation to the positive pressure side due to the execution of the cleaning may be dispersed and generated at different timings. As a result, it is possible to reduce the swaying after the deceleration shock and to make it less likely to be felt as a shock, thereby improving drivability. Also, In general, the deceleration fuel cut operation is completed in a shorter time because the engine brake is more effective as the transmission gear ratio is lower. Therefore, according to the present invention, by setting the delay time, which is the waiting time for executing cleaning, as described above, it is possible to appropriately ensure the opportunity for executing cleaning and increase the frequency of execution.
[0009]
According to a third aspect of the present invention, in the valve timing control device for an internal combustion engine according to the second aspect, the delay time setting means sets the delay time #TMVCLDY when the speed ratio is the lowest than when the speed ratio is the other. A smaller value is set (FIG. 4).
[0010]
According to this configuration, even when the engine brake is very effective and the minimum speed ratio at which the deceleration fuel cut operation is completed earliest, the opportunity for performing cleaning can be appropriately ensured.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration of a valve timing control device (hereinafter simply referred to as “control device”) for an internal combustion engine to which the present invention is applied. As shown in the figure, the control device 1 includes an ECU 2 (deceleration fuel cut determination means, cleaning control means, delay time setting means). The ECU 2 includes an internal combustion engine (hereinafter referred to as “engine”) 3. A control process as described later is executed in accordance with the operating state.
[0012]
The engine 3 is, for example, a 4-cycle DOHC type gasoline engine mounted on a vehicle (not shown), and its crankshaft 8 is connected to a drive wheel (not shown) of the vehicle 2 via, for example, a 5-speed transmission 21. ). The intake camshaft 6 and the exhaust camshaft 7 of the engine 3 are connected to the crankshaft 8 via respective driven sprockets 6b and 7b and a timing chain (not shown). It is driven to rotate at the rate of rotation. The intake camshaft 6 and the exhaust camshaft 7 are integrally provided with a plurality of intake cams 6a and exhaust cams 7a (only one is shown) for driving the intake valve 4 and the exhaust valve 5 to open and close, respectively.
[0013]
The intake camshaft 6 (camshaft) is connected to the driven sprocket 6b so as to be rotatable within a predetermined angle range. By changing the relative angle of the intake camshaft 6 with respect to the driven sprocket 6b, the phase of the intake cam 6a with respect to the crankshaft 8 (hereinafter simply referred to as “cam phase”) CAIN is changed, and the opening / closing timing of the intake valve 4 ( (Valve timing) is advanced or retarded. A cam phase varying device 11 including a cam phase varying mechanism (hereinafter referred to as “VTC”) 9 and a hydraulic control valve 10 for controlling the cam phase CAIN is provided at one end of the intake camshaft 6.
[0014]
The VTC 9 has an advance chamber and a retard chamber (both not shown) defined on both sides of a vane (not shown) integral with the intake camshaft 6, and is oil driven by the engine 3. The hydraulic pressure of a pump (not shown) is selectively supplied to the advance chamber or the retard chamber by the control of the hydraulic control valve 10, thereby causing the intake camshaft 6 to advance in the advance direction or the driven sprocket 6b. It is configured to be rotationally driven in the retard direction.
[0015]
The hydraulic control valve 10 is composed of a duty solenoid valve including a solenoid and a spool driven by the solenoid. The hydraulic control valve 10 is configured such that the position of the spool changes steplessly according to the output duty ratio DOUTVT of the solenoid current controlled by the ECU 2, and the advance chamber or retard chamber of the VTC 9 according to the position. Open and close. Specifically, when the output duty ratio DOUTVT to the hydraulic control valve 10 (hereinafter simply referred to as “output duty ratio DOUTVT”) is larger than the holding duty value (for example, 50%), the spool of the hydraulic control valve 10 is in the neutral position. To the one side to open the advance chamber, the hydraulic pressure is supplied to the advance chamber and the cam phase CAIN is advanced. On the other hand, when the output duty ratio DOUTVT is smaller than the holding duty value, the spool moves from the neutral position to the other side to open the retard chamber, thereby supplying hydraulic pressure to the retard chamber and delaying the cam phase CAIN. It becomes a retarded state that makes it horn. The movable range of the intake cam 6a is, for example, 60 ° crank angle, and is located at the BTDC 25 ° crank angle at the most retarded angle and at the BTDC 85 ° crank angle at the most advanced angle, and the cam phase CAIN is 0 at the most retarded angle position. The crank angle is 60 ° at the most advanced position.
[0016]
Further, when the output duty ratio DOUTVT is the holding duty value, the hydraulic control valve 10 is in a holding state in which the spool is positioned at a neutral position that simultaneously closes the advance chamber and the retard chamber, and enters the advance chamber and the retard chamber. Is cut off and the intake camshaft 6 and the driven sprocket 6b are integrated, so that the cam phase CAIN is maintained at the value controlled so far.
[0017]
A cam angle sensor 28 is provided at the end of the intake camshaft 6 opposite to the VTC 9. The cam angle sensor 28 includes, for example, a magnet rotor and an MRE pickup, and detects the cam angle CASVIN of the intake cam 6a with reference to TDC as the intake camshaft 6 rotates, and outputs the signal to the ECU 2. . The crankshaft 8 is provided with a crank angle sensor 29. The crank angle sensor 29 is configured in the same manner as the cam angle sensor 28, and outputs a CRK signal, which is a pulse signal, to the ECU 2 at every predetermined crank angle (for example, 30 °) as the crankshaft 8 rotates. The ECU 2 calculates (detects) the actual cam phase CAIN from the CRK signal and the CASVIN signal (hereinafter, the cam phase actually detected in this way is appropriately referred to as “actual cam phase CAIN”). Further, the ECU 2 obtains the engine speed (hereinafter referred to as “engine speed”) NE of the engine 3 based on the CRK signal.
[0018]
The intake pipe 30 of the engine 3 is provided with a throttle valve 31 to which a throttle valve opening sensor 37 is attached, and an injector 32, an intake air temperature sensor 33, and an intake pressure sensor 34 are further provided on the downstream side thereof. It is attached. The fuel injection time TOUT of the injector 32 is controlled by a drive signal from the ECU 2.
[0019]
The intake air temperature sensor 33 is an intake air temperature TA, which is the temperature of the intake air in the intake pipe 30, and the intake pressure sensor 34 is an absolute pressure (hereinafter referred to as "absolute pressure in the intake pipe") PBA in the intake pipe 30, and a throttle valve. The opening sensor 37 detects the opening (hereinafter referred to as “throttle valve opening”) θTH of the throttle valve 31 and outputs each detection signal to the ECU 2. Further, an engine water temperature sensor 35 is attached to the main body of the engine 3, and the engine water temperature sensor 35 detects the engine water temperature TW that is the temperature of the cooling water circulating in the cylinder block of the engine 3, and detects the detection. A signal is output to the ECU 2. Further, the ECU 2 receives a detection signal representing the atmospheric pressure PA from the atmospheric pressure sensor 38 from the gear position sensor 39 (transmission ratio detection means), and outputs a gear position number NGR corresponding to the gear position (transmission ratio) of the transmission 21. Representing detection signals are respectively output. As the gear position number NGR, values 1 to 5 are assigned to the first to fifth gear positions of the transmission 21, respectively.
[0020]
The ECU 2 is composed of a microcomputer including an I / O interface, CPU, RAM, ROM, and the like. The detection signals from the various sensors described above are input to the CPU after A / D conversion and shaping by the I / O interface.
[0021]
The CPU determines the operating state of the engine 3 according to these input signals, and according to the determined operating state, according to the control program and data stored in the ROM, the data stored in the RAM, etc. As described above, the control of the VTC 9 (hereinafter referred to as “VTC control”) is executed.
[0022]
FIG. 2 is a main flow showing the flow of the entire VTC control process. This control process is executed every predetermined time (for example, 10 ms). First, in step 1 (shown as “S1” in the drawing, the same applies hereinafter), it is determined whether or not the execution condition of the VTC control is satisfied according to the engine water temperature TW, the engine speed NE, and the like. Allow or prohibit. Next, it is determined whether or not the VTC 9 cleaning execution condition is satisfied (step 2). This cleaning is to forcibly drive the hydraulic control valve 10 and the VTC 9 from the most retarded position to the most advanced position in order to prevent the VTC 9 and the hydraulic control valve 10 from being stuck due to clogging. The contents of this determination process will be described later.
[0023]
Next, in step 3, the target cam phase CAINCMD is calculated according to the operating state of the engine 3, such as the engine speed NE and the intake pipe absolute pressure PBA. Next, the output duty ratio DOUTVT is calculated by feedback control in accordance with the calculated target cam phase CAINCMD and actual cam phase CAIN, and a drive signal based on the calculation result is output to the hydraulic control valve 10 (step 4). Exit. When the execution of cleaning is permitted in step 2, the output duty ratio DOUTVT is set to the upper limit value (for example, 95%) in step 4, and the cleaning is executed.
[0024]
FIG. 3 shows a subroutine of the cleaning execution condition determination process executed in step 2 of FIG. In the following description, a fixed value stored in advance as individual data or table values in the ROM is prefixed with “#” to distinguish it from other variables to be updated.
[0025]
In this process, first, in step 11, it is determined whether or not the engine water temperature TW is higher than a lower limit value #TWVTCCLG (for example, 80 ° C.). If this answer is NO and TW ≦ # TWVTCCLG, the engine 3 is not sufficiently warmed up, the temperature of the hydraulic oil of the VTC 9 is low, and its controllability is not good, so cleaning should not be executed. Then, the cleaning completion flag F_VTCCLG is set to “0” (step 22), a predetermined delay time #TMVCLDLY is set to the down-count type cleaning delay timer TVCLNDLY (step 23), and the cleaning permission flag F_VTCCLN is set to “0”. (Step 24), the predetermined time #TMVTCCLA (for example, 0.3 seconds) is set in the timer TVTCCLGA after the down-count type cleaning is executed, and the predetermined time #TMVTCCLB (for example, 1 in the same time at the cleaning end timer TVTCCLGB). 0 seconds) were each set (step 25), followed by terminating the program.
[0026]
The delay time #TMVCLDLY is set according to the gear position of the transmission 21 based on the table shown in FIG. In this table, delay times # TMVCLDLY1 to 5 are set for the gear position numbers NGR1 to NGR1 (first speed to fifth speed), respectively. These delay times # TMVCLDLY1 to 5 are basically set to smaller values as the gear position number NGR is smaller, that is, as the gear ratio is lower. For example, # TMVCLDLY1 = 2.0 seconds, # TMVCLDLY2 = 2.5 seconds and # TMVCLDLY3-5 = 3.0 seconds are set. This is because, as the gear ratio is lower, the engine brake is more effective, and the deceleration fuel cut is completed in a shorter time. Therefore, in accordance with such a tendency, an appropriate cleaning execution opportunity is ensured.
[0027]
When the answer to step 11 is YES, it is determined whether or not the engine speed NE is higher than a lower limit value #NEVTCCLG (for example, 2000 rpm) (step 12). When this answer is NO and NE ≦ # NEVTCCLG, the engine speed NE is low, so the deceleration fuel cut operation is short and may end before the cleaning is completed. Steps 22 to 26 are executed, and this program is terminated.
[0028]
When the answer to step 12 is YES, it is determined in step 13 whether or not the throttle fully closed flag F_THIDLE is “0” and in step 14 whether or not the fuel cut flag F_FC is “1”. If any of the answers to both Steps 13 and 14 is NO, that is, if the throttle valve 31 is not in the fully closed state or the deceleration fuel cut operation is not being performed, it is determined that the cleaning execution condition is not satisfied, and Steps 22 to 22 are performed. 26 is executed and the program is terminated.
[0029]
On the other hand, when the answer to steps 13 and 14 is YES, that is, TW>#TWVTCCLG and NE>#NEVTCCLG are satisfied, the throttle valve 31 is almost fully closed, and the deceleration fuel cut operation is in progress. When the cleaning execution condition is satisfied, it is then determined whether or not the cleaning completion flag F_VTCCLG is “1” (step 15). If the answer is NO and the cleaning is not yet completed, it is determined whether or not the timer value of the cleaning delay timer TVCLNDLY set in the step 23 is 0 (step 16). When the answer is NO, that is, when the delay time #TMVCLDLY has not elapsed after the cleaning execution condition is satisfied, the process proceeds to steps 24 to 26, and the execution of the cleaning is suspended.
[0030]
On the other hand, if the answer to step 16 is YES, that is, if the delay time #TMVCCLLY has elapsed after the cleaning execution condition is satisfied, the cleaning permission flag F_VTCCLN is set to “1”, indicating that the cleaning should be executed ( Step 17). As step 17 is executed, the output duty ratio DOUTVT is set to the upper limit value (for example, 95%) in step 4 of FIG. 2, so that the hydraulic control valve 10 and the VTC 9 are forcibly moved from the most retarded position to the maximum. Cleaning is executed by being driven to the advance position.
[0031]
In step 18 following step 17, it is determined whether or not the timer value of the post-cleaning timer TVTCCLGA set in step 25 is zero. When this answer is NO, that is, when the predetermined time #TMVTCCLA has not elapsed after the start of the cleaning, the process proceeds to Step 20 described later, and the cleaning is continued unconditionally. On the other hand, if the answer to step 18 is YES, it is determined whether or not the actual cam phase CAIN is equal to or greater than a predetermined value #CAINCLG (for example, 45 °) by executing cleaning (step 19). If the answer is YES and CAIN ≧ # CAINCLG, the cleaning completion flag F_VTCCLG is set to “1” on the assumption that the actual cam phase CAIN has sufficiently advanced and the cleaning is completed (step 21). Exit the program.
[0032]
On the other hand, if the answer to step 19 is NO and CAIN <#CAINCLG, it is determined whether the timer value of the cleaning end timer TVTCCLGB set in step 26 is 0 (step 20). In this case, the program is terminated. On the other hand, when the answer to step 20 is YES, that is, when the cam phase CAIN does not reach the predetermined value #CAINCLG even after the predetermined time #TMVTCCLB has elapsed after the start of the cleaning, the step 21 is executed. Finish cleaning. This is because if the maximum lead angle state is continued for a long time during the deceleration fuel cut operation, the pressure in the intake pipe continues to take the positive pressure value, and the feeling of deceleration is reduced, resulting in a loss of commerciality. This is to avoid a serious situation.
[0033]
Note that, after the cleaning completion flag F_VTCCLG is set to “1” by the execution of step 21, the answer to step 15 becomes YES, and in this case, the process proceeds to step 23 and subsequent steps. That is, after the cleaning is completed, the second cleaning is not executed as long as the execution conditions of steps 11 to 14 are continuously satisfied. Further, when any of Steps 11 to 14 is not established, the cleaning completion flag F_VTCCLG is set to “0” in Step 22, so that the next cleaning is executed when the execution condition is satisfied thereafter. Will be.
[0034]
FIG. 5 shows an operation example obtained by the processing of FIG. 3 described above, and FIG. 6 shows an operation example obtained by the conventional cleaning control in the same operation situation for comparison with FIG. That is, it is assumed that the throttle valve 31 is fully closed at time t1, and the deceleration fuel cut operation is started at time t2 thereafter (F_FC = 1). In the conventional case shown in FIG. 6, at this time, the actual cam phase CAIN is immediately driven to the most advanced position, and cleaning is performed (between times t2 and t7). For this reason, as described above, since the intake pipe absolute pressure PBA fluctuates to the negative pressure side immediately after the throttle valve is fully closed, the abrupt fluctuation fluctuates to the positive pressure side by the execution of cleaning. As a result of this pressure reaction, the backlash after the deceleration shock is increased, and this is felt as a large shock.
[0035]
On the other hand, in the case of the present embodiment shown in FIG. 5, when the deceleration fuel cut operation is started (time t2), the cleaning delay timer TVCLNDLY starts to operate, and at this time, the cleaning is not executed. The actual cam phase CAIN is held at the most retarded position. Therefore, the backlash (variation amount ΔPBA1) after the intake pipe absolute pressure PBA fluctuates to the negative pressure side due to the full closure of the throttle valve 31 is smaller than the conventional ΔPBA2 value. Thereafter, when the delay time #TMVCLDLY has elapsed from the start of the deceleration fuel cut operation (time t3), the hydraulic control valve 10 and the VTC 9 are forcibly advanced from the most retarded position by starting the cleaning. Driven to the angular position, the actual cam phase CAIN is controlled to the most retarded position. At this point in time, the intake pipe absolute pressure PBA slightly returns to the positive pressure side and is in a stable state. Therefore, even if a positive pressure is introduced into the intake pipe due to valve overlap due to the execution of cleaning, the amount of fluctuation in the intake pipe absolute pressure PBA is small.
[0036]
As described above, the fluctuation of the absolute pressure PBA in the intake pipe to the negative pressure side due to the fully closing of the throttle valve 31 and the fluctuation to the positive pressure side due to the execution of cleaning can be generated in a dispersed manner at different timings. In addition, it is possible to improve the drivability by reducing the backlash after the deceleration shock and making it less likely to be experienced as a shock. Further, as described above, the delay time #TMVCLDLY is set to a smaller value as the gear ratio of the transmission 21 is lower. Therefore, it is possible to appropriately secure a cleaning execution opportunity and increase the execution frequency. it can.
[0037]
Thereafter, when the actual cam phase CAIN becomes equal to or greater than the predetermined value #CAINCLG, the cleaning is finished (time t4), and the actual cam phase CAIN is returned to the most retarded position. When the deceleration fuel cut operation ends (F_FC = 0) (time t5) as the throttle valve 31 is depressed, the actual cam phase CAIN is controlled by feedback control according to the target cam phase CAINCMD.
[0038]
In addition, this invention can be implemented in various aspects, without being limited to embodiment described. For example, in the embodiment, the delay time #TMVCLDLY is set according to the gear ratio of the transmission 21, but this may be set to an appropriate constant value. In addition, the delay time #TMVCLDLY is set to the smallest value when the transmission 21 is in the first speed, to the intermediate value when the transmission 21 is the second speed, and to the same largest value when the transmission 21 is the third to fifth speeds. However, for the first to fifth speeds, the lower the gear ratio, the smaller the values may be, or the first gear may be set to a smaller value than in the case of other gear ratios only in the first speed. . According to the latter setting, even when the engine brake is very effective and the minimum gear ratio at which the decelerating fuel cut operation is completed earliest, the opportunity for performing cleaning can be appropriately ensured.
[0039]
Further, the embodiment is an example in which the present invention is applied to a valve timing control device in which the intake cam phase is variable. However, the present invention is a valve timing in which the exhaust cam phase is variable instead of or together with the intake cam phase. Of course, it can be applied to the control device.
[0040]
【The invention's effect】
As described above, the valve timing control device for an internal combustion engine according to the present invention has effects such as reduction of the backlash of the deceleration shock accompanying the execution of cleaning and the increase in the frequency of execution of cleaning.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a valve timing control apparatus for an internal combustion engine according to an embodiment of the present invention.
FIG. 2 is a main flow of VTC control by the control device of FIG. 1;
3 is a flowchart of a cleaning execution condition determination process subroutine of FIG. 2;
FIG. 4 is an example of a table for setting a delay time #TMVCLDY.
FIG. 5 is a timing chart showing an operation example obtained by the processing of FIG. 3;
FIG. 6 is a timing chart showing a conventional operation example.
[Explanation of symbols]
1 Control device (valve timing control device)
2 ECU (deceleration fuel cut determination means, cleaning control means, delay time setting means)
3 Engine (Internal combustion engine)
4 Intake valve
5 Exhaust valve
6 Intake camshaft (camshaft)
6a Intake cam
7a Exhaust cam
8 Crankshaft
9 VTC (Cam phase variable mechanism)
10 Hydraulic control valve
11 Cam phase variable device
21 Transmission
39 Gear position sensor (speed ratio detecting means)
CAIN cam phase
#TMVCLDY Delay time
NGR Gear position number (speed ratio)

Claims (3)

A valve timing control device for an internal combustion engine that controls the opening / closing timing of at least one of an intake valve and an exhaust valve by changing a cam phase that is a phase of at least one of an intake cam and an exhaust cam with respect to a crankshaft,
A cam phase varying device that changes the cam phase by rotating a camshaft provided with at least one of the intake cam and the exhaust cam relative to the crankshaft;
Deceleration fuel cut determination means for determining whether or not the internal combustion engine is in a fuel cut operation in which fuel supply is stopped during deceleration;
In order to prevent the cam phase variable device from sticking when a predetermined delay time has elapsed after the deceleration fuel cut operation is started , the cam phase variable device is connected to the intake valve and the exhaust valve. Cleaning control means for performing cleaning by forcibly driving in a direction in which the lap increases ;
A valve timing control device for an internal combustion engine, comprising: A valve timing control device for an internal combustion engine that controls the opening / closing timing of at least one of an intake valve and an exhaust valve by changing a cam phase that is a phase of at least one of an intake cam and an exhaust cam with respect to a crankshaft,
A cam phase varying device that changes the cam phase by rotating a camshaft provided with at least one of the intake cam and the exhaust cam relative to the crankshaft;
Deceleration fuel cut determination means for determining whether or not the internal combustion engine is in a fuel cut operation in which fuel supply is stopped during deceleration;
In order to prevent the cam phase variable device from sticking when a predetermined delay time has elapsed after the deceleration fuel cut operation is started, the cam phase variable device is forcibly forced within a predetermined cam phase range. Cleaning control means for performing cleaning by driving; and
Gear ratio detecting means for detecting a gear ratio of a transmission connected to the internal combustion engine;
Delay time setting means for setting the delay time to a smaller value as the detected gear ratio is lower;
A valve timing control device for an internal combustion engine, comprising:   3. The valve for an internal combustion engine according to claim 2, wherein the delay time setting means sets the delay time to a smaller value when the speed ratio is the lowest than at other speed ratios. Timing control device.

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